Spread spectrum signature reduction

ABSTRACT

A system and method for secure communications is disclosed which includes a processor(s) of a first appliqué spreading an uplink signal of a user from user equipment, where the first appliqué is coupled to the user equipment, and where the user equipment is connected to a mobile network. The processor(s) frequency shifts the spread uplink signal to maintain orthogonality over the mobile network.

BACKGROUND OF INVENTION

Long-Term Evolution (LTE) systems (including handsets or user equipment(UE) and associated radio access networks), originally developed forcommercial applications, are being adapted for military uses. The largeproduction volumes of commercial technology and marketplace competition,have led to a degree of integration, miniaturization, lowering of cost,and ease-of-use while dedicated tactical radio has not experienced asimilar pace of advances. Rapid technology evolution in the commercialmarketplace is also more attractive than tactical radio technology. Forexample, compact mobile tactical LTE networks (e.g., systems availablefrom PacStar, General Dynamics, Oceus, Harris, etc.) are currentlyavailable, enabling tactical units to use (on the move or at the halt)dedicated networks that do not depend on in-country hosts.

Although integrating commercial solutions into tactical solutionsprovides access to useable technology, integrating consumerfunctionality into military environments can introduce securityconcerns. Existing LTE solutions, including those customized fortactical applications, are vulnerable to electronic (and potentiallykinetic) threats because these systems typically need to rely onenabling commercial chipsets, which specify the over-the-air waveform,and need to be inter-operable with other equipment. Thus, currentlyavailable tactical LTE systems are subject to detection, interception,geolocation, jamming, spoofing and other electronic warfare techniques,putting warfighters at risk.

SUMMARY OF INVENTION

Shortcomings of the prior art are also overcome and additionaladvantages are provided through the provision of a system for securingcommunications over a network. The computer system can include: a firstappliqué comprising at least one processor, coupled to user equipmentconnected to a mobile network; the user equipment configured tocommunicate with Evolved Node B hardware over the mobile network; asecond appliqué comprising at least one processor, coupled to theEvolved Node B hardware, configured to receive communications from theuser equipment and to process and transmit the communications to theEvolved Node B hardware; and the Evolved Node B hardware, wherein thefirst appliqué spreads an uplink signal of a user from the userequipment and frequency shifts the uplink signal, so that the spreaduplink signal maintains orthogonality over the mobile network, andwherein the second appliqué obtains the spread uplink signal from theuser equipment and processes the spread uplink, the processing by thesecond appliqué comprising: utilizing embedded training sequences toequalize and de-spread each symbol of the spread uplink signal togenerate a de-spread and frequency-shifted signal; re-combining thede-spread and frequency-shifted signal using an aggregator to generate arecombined signal; and providing the recombined signal to the EvolvedNode B hardware.

In some examples, the user equipment is user equipment of a long-termevolution system. In some examples, the Evolved Node B hardwarecomprises a base transceiver station. In some examples, the userequipment comprises a mobile handset.

In some examples, the first appliqué spreads an uplink signal utilizinga spreading code unique to the user. The spreading code can be providedto the user equipment by the second appliqué and the spreading code canbe provided to the first appliqué by the user equipment.

In some examples, the first appliqué spreads the uplink signal of theuser from the user equipment by performing activities comprising:determining a beginning of each uplink (UL) waveform subframe and symbolperiod in the uplink signal, wherein the uplink signal comprises awaveform; utilizing the beginning of each UL waveform subframe andsymbol period to align a spreading code with the waveform; generating,from the uplink signal, a spreading waveform and a local oscillator at agiven frequency; embedding the training sequences in the waveform; andapplying the spreading waveform and the local oscillator at the givenfrequency to the waveform with the training sequence to generate thespread uplink signal. The applying can comprise performing a complexbaseband modulation. The training sequences added to the waveform can beorthogonal or approximately orthogonal to the waveform. In someexamples, the given frequency is selected from the group consisting of:a fixed frequency and a dynamic frequency, wherein the dynamic frequencychanges at pre-determined times.

Shortcomings of the prior art are also overcome and additionaladvantages are provided through the provision of a computer-implementedsystem for securing communications over a network. The method caninclude: spreading, by one or more processors of a first appliqué, anuplink signal of a user from long-term evolution system user equipment,wherein the first appliqué is coupled to the long-term evolution systemuser equipment, and wherein the long-term evolution system userequipment is connected to a mobile network; and frequency shifting, bythe one or more processors of the first appliqué, the spread uplinksignal to maintain orthogonality over the mobile network.

In some examples, the method further comprises: obtaining, by one ormore processors of a second appliqué, over the mobile network, thespread uplink signal, wherein the second appliqué is coupled to EvolvedNode B hardware, and wherein the Evolved Node B hardware is configuredto receive communications from the long-term evolution system userequipment; and processing, by the one or more processors of the secondappliqué, the spread uplink signal, wherein the processing comprises:utilizing embedded training sequences to equalize and de-spread eachsymbol of the spread uplink signal to generate a de-spread andfrequency-shifted signal; and re-combining the de-spread andfrequency-shifted signal using an aggregator to generate a recombinedsignal; and providing, by the one or more processors of the secondappliqué, the recombined signal to the Evolved Node B hardware.

In some examples, the method further comprises: obtaining, by the one ormore processors of a first appliqué, from the long-term evolution systemuser equipment, a spreading code, wherein the spreading comprisesutilizing the spreading code. In some examples, the spreading code isunique to the user.

The method can further comprise: assigning, by the one or moreprocessors of a second appliqué, to the long-term evolution system userequipment, the spreading code. This assigning can include, for example:accessing, by the one or more processors of a second appliqué, anout-of-band channel; and utilizing, by the one or more processors of asecond appliqué, the out-of-band channel to assign the spreading code.This spreading can further comprise: determining, by the one or moreprocessors of the first appliqué, a beginning of each uplink (UL)waveform subframe and symbol period in the uplink signal, wherein theuplink signal comprises a waveform; utilizing, by the one or moreprocessors of the first appliqué, the beginning of each UL waveformsubframe and symbol period to align a spreading code with the waveform;generating, by the one or more processors of the first appliqué, fromthe uplink signal, a spreading waveform and a local oscillator at agiven frequency; embedding, by the one or more processors of the firstappliqué, the training sequences in the waveform; and applying, by theone or more processors, the spreading waveform and the local oscillatorat the given frequency to the waveform with the training sequence togenerate the spread uplink signal.

In some examples, the training sequence added to the waveform isorthogonal or approximately orthogonal to the waveform.

In some examples, the given frequency is selected from the groupconsisting of: a fixed frequency and a dynamic frequency, where thedynamic frequency changes at pre-determined times.

Shortcomings of the prior art are also overcome and additionaladvantages are provided through the provision of a computer-implementedsystem for securing communications over a network. The method caninclude: obtaining, by one or more processors of a second appliqué, overthe mobile network, a spread uplink signal, wherein an uplink signalspread to generate the spread uplink signal originated from long-termevolution system user equipment, wherein the second appliqué is coupledto Evolved Node B hardware, and wherein the Evolved Node B hardware isconfigured to receive communications from the long-term evolution systemuser equipment; and processing, by the one or more processors of thesecond appliqué, the spread uplink signal, wherein the processingcomprises: utilizing embedded training sequences to equalize andde-spread each symbol of the spread uplink signal to generate ade-spread and frequency-shifted signal; and re-combining the de-spreadand frequency-shifted signal using an aggregator to generate arecombined signal; and providing, by the one or more processors of thesecond appliqué, the recombined signal to the Evolved Node B hardware.

Systems, methods, and computer program products relating to one or moreaspects of the technique are also described and may be claimed herein.Further, services relating to one or more aspects of the technique arealso described and may be claimed herein.

Additional features are realized through the techniques of the presentinvention. Other embodiments and aspects of the invention are describedin detail herein and are considered a part of the claimed invention.

BRIEF DESCRIPTION OF DRAWINGS

One or more aspects of the present invention are particularly pointedout and distinctly claimed as examples in the claims at the conclusionof the specification. The foregoing and objects, features, andadvantages of one or more aspects of the invention are apparent from thefollowing detailed description taken in conjunction with theaccompanying drawing.

FIG. 1 depicts various aspects of some embodiments of the presentinvention.

FIG. 2 is an example of an alignment of the spreading code with thetransmitted waveform for ASPU computed significant changes in deviceemanation behavior by program code in some embodiments of the presentinvention.

FIG. 3 illustrates ASPU spreading showing a combination of directsequence and frequency shifts per sub-frame in some embodiments of thepresent invention.

FIG. 4 illustrates the performance of ASPU spreading, as facilitated byprogram code in various embodiments of the present invention, for asingle user with the spreading factor (SF) equal to 32.

FIG. 5 illustrated the performance of the ASPU receiver with a singleuser, in some embodiments of the present invention, where N_(rx)=1 and 4(with and without spreading).

FIG. 6 is a connection state diagram for an appliqué at the userequipment and an appliqué at the E-UTRAN Node B or Evolved Node B(eNodeB), both appliqués being aspects of some embodiments of thepresent invention.

FIG. 7 depicts a workflow illustrating certain aspects of an embodimentof the present invention.

FIG. 8 depicts a workflow illustrating certain aspects of an embodimentof the present invention.

FIG. 9 depicts a workflow illustrating certain aspects of an embodimentof the present invention.

FIG. 10 depicts a computer system configured to perform an aspect of anembodiment of the present invention.

FIG. 11 depicts a computer program product incorporating one or moreaspects of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the present invention and certain features, advantages, anddetails thereof, are explained more fully below with reference to thenon-limiting examples illustrated in the accompanying drawings.Descriptions of well-known materials, fabrication tools, processingtechniques, etc., are omitted so as not to unnecessarily obscure theinvention in detail. It should be understood, however, that the detaileddescription and the specific examples, while indicating aspects of theinvention, are given by way of illustration only, and not by way oflimitation. Various substitutions, modifications, additions, and/orarrangements, within the spirit and/or scope of the underlying inventiveconcepts will be apparent to those skilled in the art from thisdisclosure. The terms software and program code are used interchangeablythroughout this application and can refer to logic executed by bothhardware and software. Components of the system that can be utilized toexecute aspects of embodiments of the present invention may includespecialized hardware, including but not limited to, an FPGA and a GPU(graphics professor unit). Additionally, items denoted as processors mayinclude hardware and/or software processors or other processing means,including but not limited to a software defined radio and/or customhardware.

Embodiments of the present invention include a computer-implementedmethod, a computer program product, and a system that include programcode executed by at least one processing resource that: 1) protects anLTE waveform from interference; and 2) protects the LTE waveform frominterceptors. Embodiments of the present invention include program codeand/or one or more devices executing program code, that simultaneouslylowers the vulnerability of LTE waveforms to detection and geolocationby threat receivers and provides robustness to jamming, while making useof an unmodified LTE UE and E-UTRAN Node B or Evolved Node B (eNodeB).An eNodeB is hardware that is connected to a mobile phone network thatcommunicates directly, wirelessly, with mobile handsets (UEs), includingbut not limited to, a base transceiver station (BTS). Embodiments of thepresent invention provide additional security measures in communicationsthat enable, e.g., the military to use commodity commercial equipment.Thus, embodiments of the present invention provide spread spectrumsignature reduction for LTE. Although certain implementations that areillustrated herein support LTE, aspects of some embodiments of thepresent invention also provide protection for other wirelesstechnologies, such as 5G systems, which may use related waveforms.

Embodiments of the present invention include program code implemented ona mobile device utilizing 1) a compact appliqué at the UE; and 2) acorresponding appliqué at the eNodeB. Thus, the program code equalizesand aggregates before presenting to the eNodeB. While some embodimentsof the present invention provide spread spectrum signature reduction forLTE related to the uplink, some embodiments of the present inventionprovide spread spectrum signature reduction for LTE at the downlink.Because of its implementation through appliqué, aspects of variousembodiments of the present invention can be utilized with unmodifiedhandsets and base station equipment. Thus, LTE infrastructure and basestation equipment can be procured separately and aspects of the presentinvention can be implemented in the existing infrastructure but theseaspects modify the over-the-air waveform sufficiently to provide therequired protection, regardless of the existing underlyinginfrastructure.

A shorthand used throughout this application is “SPIRAL”, which standsfor spread spectrum signature reduction for LTE. The combination ofletters used to form this shorthand does not rely on the first lettersof the words, in every case, but the shorthand was created and usedthroughout to reduce the need to repeat the phrase “spread spectrumsignature reduction for LTE.”

The terms “substantially”, “approximately”, “about”, “relatively,” orother such similar terms that may be used throughout this disclosure,including the claims, are used to describe and account for smallfluctuations, such as due to variations in processing, from a referenceor parameter. Such small fluctuations include a zero fluctuation fromthe reference or parameter as well. For example, they can refer to lessthan or equal to ±10%, such as less than or equal to ±5%, such as lessthan or equal to ±2%, such as less than or equal to ±1%, such as lessthan or equal to ±0.5%, such as less than or equal to ±0.2%, such asless than or equal to +0.1%, such as less than or equal to +0.05%. Ifused herein, the terms “substantially”, “approximately”, “about”,“relatively,” or other such similar terms may also refer to nofluctuations. To that end, there are various numerical values providedin certain of the figures filed herewith which are provided for thepurpose of giving some examples of values relevant to some embodimentsof the present invention. They are meant to illustrate and not to limitthe values. Even as examples, each value provided is a relative valuethat is meant to cover the fluctuations described above as well as nofluctuations.

FIG. 1 illustrates an implementation 100 of aspects of an embodiment ofthe present invention in a mobile device. As depicted in FIG. 1,embodiments of the present invention comprise an appliqué 110 at the UE105 (a first appliqué) and an appliqué 120 at the eNodeB 115 (a secondappliqué). The UE appliqué 110 is also referred to herein as the UESPIRAL appliqué or the UESA; these terms may be used interchangeablythroughout this disclosure. The eNodeB appliqué 120 is likewise referredto by some different terms throughout this application, including theeNodeB SPIRAL appliqué and the ESA.

Returning to FIG. 1, the UE 105 and the eNodeB 115, as noted in FIG. 1,are unmodified. FIG. 1 illustrates how program code executing at thefirst appliqué 110 spreads 126 the uplink signal 136 of a user (of themobile computing device 105). In some embodiments of the presentinvention, the program code executing at the first appliqué 110 can beexecuted by the UESA controller 129. Program code in embodiments of thepresent invention frequency shifts (and/or optionally frequency hops),so that spread signals 117 from each UE 105 maintain orthogonalityover-the-air 122. Program code executing at the second appliqué 120processes each UE's 110 spread signal 117 using, for example, the MAED(Multi-Aperture Equalizer/De-spreader) 128, which uses an embeddedtraining sequences to equalize and de-spread each symbol, for each user134. The program code executing at the second appliqué 120 is executed,in some embodiments of the present invention, by a controller in thesecond appliqué 120, depicted herein as an ESA controller 133.

The program code re-combines the resulting de-spread andfrequency-shifted signals using an aggregator 137, for presentation tothe unmodified eNodeB 115 (see, e.g., the second appliqué 120-eNodeB 115interface 141), of the processing results 144, for each UE. Theout-of-band (OOB) control channel 118 allows program code of the eNodeBappliqué 120 to assign spreading codes, to manage frequency assignments,and/or to provide fine-grain close-loop spreading code offsetadjustments. Thus, aspects of embodiments of the present inventionenables direct sequence cover of the underlying LTE waveform, as well asfrequency shifting/hopping. In addition to the illustration in FIG. 2,FIG. 7, which will be discussed herein, illustrates various aspects ofthe method of the present invention.

FIG. 2 depicts the program code aligning of the spreading code with thetransmitted waveform utilizing the Arbitrary Spreading per User (ASPU)approach 200 depicted in FIG. 1. This ASPU approach 200 permits adifferent spreading code to be applied to each user and enables per-userspace time equalization prior to de-spreading, allowing the system toexploit enhanced diversity due to spreading, allowing seamlessintegration with techniques for interference mitigation. FIG. 2 depictsthe processing of a Physical Uplink Shared Channel (PUSCH) transmissionform a LTE UE (e.g., FIG. 1, 105) to the spreading sequence from theappliqué (e.g., FIG. 1, 120). Embodiments of the present inventioninclude program code that provides full arbitrary coverage of the LTEwaveform, preventing an adversary intercept receiver from exploitingwell-known LTE uplink components such as the DMRS (demodulationreference signal) SRS (sounding reference signal), and also preventingan intercept receiver from exploiting cyclic features in the underlyingwaveform such as via the Schmidl-Cox algorithm. For example, in someembodiments of the present invention, the program code lowers theinstantaneous peak power spectral density relative to the unmodified LTEwaveform by a factor of 10 log 10(SF) dB (SF is the spreading factor).

FIG. 3 depicts this ASPU (approach) 300 to spreading showing acombination of direct sequence and frequency shifts, per sub-frame.Different aspects of the approach 300 are depicted in FIG. 3, from thefrequencies as generated by the unmodified UE 310, to the ASPU spreadwaveform over the air 315, to the after de-spreading re-assembly 320.Four users are provided in this example, each on a Physical UplinkShared Channel (PUSCH): User 1 PUSCH, User 2 PUSCH, User 3, PUSCH, andUser 4 PUSCH. Illustrated in FIG. 3 are also an UE SPIRAL (spreadspectrum signature reduction for LTE) appliqué spread 340 and an eNodeBSPIRAL appliqué de-spread 350. As noted in FIG. 3, the frequency axishas different scales for different axes. There are various valuesprovided in FIG. 3 that are examples of values that are relevant to someembodiments of the present invention.

As illustrated in FIG. 3, utilizing ASPU 300, in embodiments of thepresent invention, the program code utilizes a different spreadingsequence and an orthogonal frequency hopping pattern, for each user.Orthogonality is maintained between users over the air, thus, theprogram code in embodiments of the present invention does not introduceco-channel interference, and higher Channel Quality Indicator (CQI)formats can be used. In some embodiments of the present invention, theprogram code facilitates per-user equalization, prior to de-spreading,as illustrated in FIG. 1. By facilitating per-user equalization, theprogram code reduces the transmit power per UE (e.g., by approximately 5dB in the TU channel, relative to the SAS single-tap rake receiver) asshown in FIG. 4, which depicts the performance of ASPU spreading, by theprogram code, in embodiments of the present invention, for a single userwith SF=32, using different receiver structures. In some embodiments ofthe present invention, the program code applying an embedded trainingsequence permits per-slot equalization and fast hopping (in someembodiments, up to 14000 times/sec). Embodiments of the presentinvention provide an advantage over existing appliqué-based approaches,which are limited to hopping at no faster than the sub-frame rate (1000times per second).

Returning to FIGS. 1 and 3, and as aforementioned, utilizing an ASPU 300permits a different spreading code 310, 330, 315 to be applied to eachuser (e.g., User 1, User 2, User 3, and User 4) and enables per-userspace time equalization 315 prior to de-spreading 340, allowing thesystem to exploit enhanced diversity due to spreading, allowing seamlessintegration with techniques for interference mitigation. In embodimentsof the present invention, over the air 112, each user is spread 126, 117and frequency shifted (hopped) to maintain orthogonality with otherusers' signals. Hopping on a per-slot basis is enabled by embeddedtraining signals (inserted by the program code of the UE appliqué 110 asa training sequence insertion aspect 124) and per-UE 105 equalization.The eNodeB appliqué 120 works as an aggregator. The program codeperforms fine time alignment tracking, performing fine offset timealignment 137 (to within something small relative to a chip period for ausable multipath component). The program code that performs thespreading 126, 117 utilizes spreading codes aligned at the UE appliqué110 with the transmitted waveform, so the spreading-code to DMRSalignment is fixed. However, program code in embodiments of the presentinvention can utilize arbitrary spreading codes. When assigningspreading codes, the program code can assign a single code to all usersin a cell, as Cell-Specific Spreading Codes (CSSC), or a single codeacross the whole system, as Universal Spreading Codes (USC). Thus, eachuser is assigned a code/frequency offset (or hop sequence), that it usesin all cells. With CSSC, program code executed by each UE appliqué 110manages its own codes. As each UE 105 occupies a distinct band afterspreading, the technique does not introduce additional Co-ChannelInterference (CCI), thus, the program code can utilize high CQI formats.In some embodiments of the present invention, the codes utilized by theprogram code of each UE appliqué 110 are stored in a central location, acommon pool, including but not limited to a resource of a sharedcomputing environment, such as a cloud computing environment, and theresource can be utilized or referenced for cell switch and hand-off.

In embodiments of the present invention, the UE appliqué 110 does notintroduce significant latency to an uplink transmission. In someembodiments, before an eNodeB appliqué-specific code/frequency (CF) isassigned by the program code, the program code spreads Physical RandomAccess Channels (PRACHs) utilizing eNodeB appliqué 120 watering holes,spreading code/frequency combinations (the WHCFs 128), although theremay be collisions between the PRACHs generated by different users on theWHCF 128.

In some embodiments of the present invention, the program code performsper-UE equalization before de-spreading, using the code-aligned DMRSand/or embedded training sequences. Some embodiments of the presentinvention perform joint per-UE equalization and spatial processing.Although each user occupies a distinct subband over the air, so theusers and the bands do not instantaneously cover each other, the usersand bands can combine with frequency hopping, and can use decoys.

The second appliqué 120, the eNodeB appliqué in FIG. 1, in oneembodiment of the present invention (offered by way of example) operateswith SF=32 (utilizing a chip rate of 61.44 Mchips per second and anominal bandwidth of about 61.44 MHz). As understood by one of skill inthe art, in FIG. 1, 61.44 Mchip/sec is shown for reference, but otherspreading rates (higher and lower) are possible, utilizing aspects ofvarious embodiments of the present invention. Some embodiments of thepresent invention include a second appliqué, which utilizes multipleantennas. In embodiments of the present invention with eNodeB appliquémulti-antenna operation, at a receiver, for each user, the program codedetermines the fast Fourier transform (FFT) (i.e., an algorithm thatsamples a signal over a period of time (or space) and divides it intoits frequency components) of each useful part of the signal (formultiple antennas), so that the received signal corresponding to FFTfrequency bin m is:{tilde over (y)} _(m) =h _(X,k,m) {tilde over (x)} _(k,m) +h _(V,m){tilde over (v)} _(m) +ñ _(m)  (1)

In (1) above, {tilde over (x)}_(k,m) is the DFT representation atsubcarrier m of signal-of-interest (SOI), {tilde over (v)}_(m) is ajamming signal, and ñ_(m) is noise. The spatial signatures are{h_(X,k,m)} and {h_(V,m)} for SOI k and jammer, respectively atsubcarrier m. A frequency domain vector (array) weight for subcarrier mis applied. In the simulation, where the channels {h_(X,k,m)} and{h_(V,m)} are known, the program code can obtain the Minimum Mean SquareError (MMSE) weight vector in the presence of a jamming signal via:w _(m)=(h _(X,k,m) h _(X,k,m) ^(H) P _(X,k,m) +h _(V,m) h _(V,m) ^(H) P_(,m) +I _(N) _(r) _(,N) _(r) P _(N,m))⁻¹ h _(X,k,m) P _(X,k,n)  (2)

In (2) above, P_(X,k,m) is the received power from k, where P_(V,m) isthe received power from jammer, and P_(N,m) is the noise power. Underslow-hopping conditions, if the program code does not track the channel,the program code can generate a correlation matrix based implementation,obtaining the equalized (and interference-nulled) signal is obtained by:{tilde over (z)} _(m) =w _(m) ^(H) {tilde over (y)} _(m)  (3)

In some embodiments of the present invention, the program code convertsthe signal back into the time domain (via IDFT), and de-spread using thechip sequence a_(k)(t). The program code re-aggregates the resultingsignals from all users to reconstitute the signal that the eNodeB Rxmodem is expecting.

In some embodiments of the present invention, at the second appliqué,the eNodeB appliqué in FIG. 1, latency is introduced by the program codeduring a space-time equalization process. For frequency-domainequalization, the program code processes integers comprising SC-FDMAsymbols, enabling the program code to process the signal and prepend thecyclic prefix

As depicted in FIG. 3, various embodiments of the present inventioninclude program code that spreads physical uplink channels, includingbut not limited to, Physical Uplink Shared Channel (PUSCH), PhysicalUplink Control Channel (PUCCH), and/or Physical Random Access Channel(PRACH). In some embodiments of the present invention, the program codeachieves spreading rates of 1.92, . . . , 61.44 Mcps. The value 1.92, .. . , 61.44 Mcps refers to 1.92 to 61.44 Megachips/sec, which is spreadspectrum terminology referring to the number of spreading symbols (orchips) in millions per second. The term “chip” is used rather than“symbol” because each chip does not convey information, but is instead avariation applied to the waveform (e.g., multiplying by +/−1 for a chipduration) to spread the bandwidth and enable reception only by areceiver with knowledge of the same chip sequence. In some embodimentsof the present invention, for a six (6) resource block PUSCH allocation(72 occupied carriers), the chips rates achieved by the hardware andsoftware (e.g., program code) correspond to spreading factors of SF=1.8,. . . , 56.9 or 2.5, . . . , 17.6 dB, before accounting for additionalgain due to hopping. SF=1.8, . . . , 56.9 or 2.5, . . . , 17.6 dB is thespreading factor, first in linear terms (1.8, . . . 56.9) and indecibels (2.5, . . . , 17.6 dB). The spreading factor defines the amountof bandwidth expansion relative to the original unspread signal, so thatif the original signal has a bandwidth B, then the spread version willhave bandwidth SF×B. This is also the amount that the power spectraldensity is reduced. If the original signal has power spectral density S,then the spread power spectral density is S/SF.

Aspects of various embodiments of the present invention protect an LTEwaveform from interference. Embodiments of the present invention provideadvantages over un-modified LTE systems by lowering the vulnerability ofLTE waveforms and protecting the waveforms from interference, asillustrated in FIG. 5. FIG. 5 illustrates the performance of theun-modified LTE system in the presence of a barrage jammer, as well asperformance of the system utilizing the spreading (e.g., SF=32) aspectof embodiments of the present invention. With spreading, as facilitatedby program code it embodiments of the present invention, the systemoperates with full throughput in the presence of jamming. Theutilization of ASPU by the program code permits seamless integration ofthe appliqué and accompanying hardware and software components into theLTE system, enabling the program code to mitigate multi-apertureinterference. For a four aperture receiver (e.g., using a SISO LTEtransmission mode), embodiments of the present invention can operatewith full throughput (272 kbps) in the presence of jamming with orwithout spreading.

Aspects of some embodiments of the present invention protect an LTEwaveform from interceptors. In embodiments of the present invention, theprogram code provides arbitrary spreading, which protects the waveformfrom interceptors designed to detect LTE UL (uplink) components such asthe DMRS and/or SRS. As aforementioned, embodiments of the presentinvention, the program code also covers the cyclic prefix, preventingvulnerability to Schmidl-Cox type detectors. In one non-limiting exampleof an embodiment of the present invention, the program code offersfurther reductions in detectability by allowing the transmitter tooperate at up to 2.5 dB lower total transmit power for CQI=3 comparedwith un-spread LTE. As understood by one of skill in the art, thisbenefit is obtained through exploitation of additional diversity, asshown in FIG. 4 (e.g., for a minimal PUSCH occupying 72 adjacentsubcarriers).

In some embodiments of the present invention, aspects of the presentinvention can be utilized in-band decoy transmitters. In theseimplementations, program code in the eNodeB appliqué cancels (bysubtracting) the additive interference of the decoys, so they do notdegrade performance of the desired link, but they severely degrade theability of intercept receivers to detect and geo-locate protectedemitters. In some embodiments of the present invention utilizes in thesetransmitters, frequency hopping is accomplished at a fast rate,including, in some implementations, up to 14000 hops/sec.

Returning to FIG. 1, program code in embodiments of the presentinvention, including the program code executed in both appliqués 110,120, protects the LTE uplink, providing protection to vulnerablehandsets. Some embodiments of the present invention also protect thedownlink, spreading frequencies to provide balanced protection for bothlink directions. In some embodiments of the present invention, a lowrate downlink control channel utilized for spreading code management canbe integrated with the downlink spreading function, eliminating the needfor the OOB control channel 118.

As discussed above, embodiments of the present invention provide forfrequency hopping. Embodiments of the present invention can supportvarious hopping schemes, including: 1) slow hopping, where hops areperformed at the subframe rate (1000 Hz) or slower, and equalization ishandled by an LTE eNodeB modem Rx handle equalization using the DMRSas-is (e.g., using SAS); and 2) fast hopping where we can hop at thesymbol rate (14000 Hz).

In embodiments of the present invention that support fast hopping,embedded training sequences are utilized because embodiments of thepresent invention only enable two DMRSs per frame. Thus, if hoppingoccurs at a symbol boundary, the program code utilizes a separatetraining signal. The program code inserts a training signal (e.g., FIG.1, 124) that is spectrally orthogonal to the underlying LTE signaland/or one signal on each side. The program code spreads (e.g., FIG. 1,126) the training signal with the same ASPU waveform and utilizes thissignal for equalization. Thus, the program code can strip this signalbefore aggregation in the ASPU receiver.

As depicted in FIG. 1, in embodiments of the present invention, theprogram code of the eNodeB appliqué may assign spreading codes, tomanage frequency assignments, and/or to provide fine-grain close-loopspreading code offset adjustments and the program code that performs thespreading utilizes spreading codes aligned at the UE appliqué with thetransmitted waveform, so the spreading-code to DMRS alignment is fixed.However, for UE spreading, the sequences utilized may be generated atthe transmitter per (4) below, where f_(k,n) is the frequency shift usedat time n, {C_(k,n)} is the chip sequence, and ϕ_(k,n) providedcontinuity. T_(c) is the chip period, which is assumed to be constant,but could be variable or dithered in future versions.

$\begin{matrix}{{a_{k}(t)} = {\sum\limits_{n = {- \infty}}^{\infty}{C_{k,n}{\Pi\left( \frac{t - {nT_{c}}}{T_{c}} \right)}e^{j{({{2\pi\; f_{k,n}t} + \phi_{k,n}})}}}}} & (4)\end{matrix}$

As illustrated in (4) above, the frequency shifts are aligned with theframe boundary for slow hopping, or the symbol boundary for fast hoppingand the sequences may be programmable. In one example, chip rates ofSF×1.92 Mcps for SF=1, 2, 4, 8, 16, and 32 are assumed. For a minimalPUSCH assignment with 6 RBs, occupying 72 adjacent carriers, with an FFTsize of 128), an actual spreading gain that is 128/72×SF can beachieved. In some embodiments of the present invention, the offsets inchip frequency for the different nodes are small relative to use ofclosed loop timing control to track and align the codes. Arbitraryadjustments can be made 10 times per second, such that the offset infrequency is small relative to 10 Hz. High quality oscillators can beutilized to minimize tracking issues. In some types of hopping withASFU, the program code can insert training references in addition tospreading, as discussed above.

As aforementioned, in ASPU, which is utilized in embodiments of thepresent invention, the alignment between the spreading sequence and theunderlying LTE waveform are fixed so that the DMRSs are registeredrelative to the spreading sequence. Thus, program code executing at theUE appliqué and the eNodeB appliqué (FIG. 1) both know the sub-framenumber s, and that the spreading sequence is aligned so that chip m=0 isaligned with the beginning of each sub-frame. Based on the code assignedto each UE, the program code of both the UE appliqué and the eNodeBappliqué generate the same sequence down to this unknown time offset.

Referring to FIG. 2, in a non-limiting example, offered for illustrativepurposes only, there are 1920×SF chips, {C_(k,s,m)} for user k, subframes, m=0, . . . (1920×SF−1), ali eNodeB eNodeB gned (e.g., FIG. 2), wherechips (412×SF)+0 . . . (137×SF−1) spread the first DMRS, and chips(1372×SF)+0 . . . (137×SF−1) spread the second DMRS. At the receiver,the program code can form a spread version of the DMRSs expected in eachsub-frame. This spread can be used to estimate the channel for thespread waveform. The program code at the UE appliqué recognizes thebeginning of each sub-frame, (to set and generate m=0), and the programcode at the UE appliqué obtains the sub-frame number s, obtaining timingto an error small relative to 1 ms (e.g., one sub-frame).

Embodiments of the present invention can utilize different spreadingsequences. Program code at the UE appliqué or the transmitter canutilize a spreading function that generates a unique spreading sequence{C_(k,s,m)}. Some embodiments of the present invention may utilize aGold sequence seeded for m=0, with a seed determined (deterministically)from (k, s).

Embodiments of the present invention handle Random Access Channel (RACH)bursts. The RACH is used by the mobile station to request a dedicatedchannel from the base station. The RACH is sent on the random accessburst, which is the first burst sent to the base station by the mobilestation, when a call origination or data connection is attempted.Because embodiments of the present invention utilize ASPU, the RACHburst is spread when the program code of the UE appliqué spreads theRACH burst using {C_(k,s,m)} where the first chip is aligned to start atthe beginning of the RACH burst. In embodiments of the presentinvention, the program code of the UE appliqué waits to spread the LTEUE signal until it observes (through monitoring and/or receives anotification of) a transmission from the UE. Upon aligning the firstchip with the start of the sub-frame, the program code of the UEappliqué can determine the subframe number s, based on the time to anerror being small relative to each sub-frame. By utilizing a clockingcomponent or signal integrated into the UE appliqué, the program code atthe UE appliqué identifies a starting burst for each sub-frame andcommence generating the spreading sequence per the alignment.

In some embodiments of the present invention, the program code detectsthe start of a sub-frame transmission at the start of the slot. Forexample, if there are several slots in a row, the program code canlocate the cyclic prefix. In one example, offered for illustrativepurposes, if the transmitter is in steady state, at SF=1, there are 138chips (CP length=10 chips) in the first symbol of the slot and 137 chips(CP length=9 chips) in the next 6 symbols. In some embodiments of thepresent invention, the program code of the UE appliqué identifies burststhat start at the beginning of a sub-frame, in order to detect the startof the transmission.

Returning to FIG. 1, at the UE, program code in an embodiment of thepresent invention spreads and frequency converts the UE waveform. Inorder to accomplish the spreading and converting, in some embodiments ofthe present invention, a modulator 148 (e.g., complex basebandmodulation) upconverts or downconverts the UE signal after spreading126.

Embodiments of the present invention include certain control functions,such as the ability to define which messages are carried over a channel,to make sure that the rates are suitable for the commercially availableoff-the-shelf devices utilized. In embodiments of the present invention,the program code of each UE appliqué 110 is pre-configured to recognizea time to an error that is small, relative to each sub-frame, so thatthe sub-frame number s can be uniquely determined. Since the code isdetermined by (k, s), pre-configuring the UE appliqué 110 includesproviding, from a control device in communication with the UE appliqué110, with an identifier for each UE which node is (k), such that theprogram code can determined s from the time.

In order to maintain {k} to be unique to each cell, aspects of variousembodiments of the present invention determined which k is mapped towhich user (e.g., Cell-Specific Spreading Codes, CSSC). In someembodiments of the present invention, {k} is common across the pool ofall users (i.e., in all cells). However, in some embodiments of thepresent invention, the program code determines which ks are associatedwith the users for a particular cell (e.g., Universal Spreading Codes,USC). As the downlink is not modified, the UE can make measurements ofsurrounding cells as normal, to identify this value. In USC, the programcode assigns a k to each user in the system and all eNodeBs look for allspreading codes, such that the eNodeB appliqué continuously monitors forall CFs. For CSSC, certain aspects of the present invention track whichusers are in which cells and assign them appropriate spreading codes.For example, when an UE switches cells, the program code de-allocatesthe user from the current cell and assign it a spreading code in the newcell.

The UESA and the ESA can share a mechanism for generating directsequence and optional spreading sequences so that, given a useridentifier k and subframe number s, both nodes can generate identicalspreading sequences. For example, the spreading code could be generatedusing a Gold code sequence generator in which a unique seed isdetermined by (k,s), from a table, which is pre-determined and shared atboth the UESA and the ESA. The Gold code sequence generated from thisgenerator (using the same generator polynomials) will then be the sameat both the UESA and the ESA. Because this approach, typical ofapproaches in commercial applications, is potentially vulnerable tophysical layer exploitation, embodiments of the present invention canalso use alternative code generation approaches.

As illustrated in part by FIG. 6, in embodiments of the presentinvention that utilize CSSC, to track which users are in which cells andassign them appropriate spreading codes, each eNodeB appliqué includesprogram code that works as a scanning receiver 600. In some embodimentsof the present invention, an UE appliqué transmits a longer probe whenit switches cells, allowing the program code to detect, based on theprobe, whenever the UE switches frequencies at the UE appliqué. In someembodiments of the present invention, a common watering holecode/frequency (CF) is used by all users to scan. Referring to FIG. 1,as well as FIG. 6, when a user switches cells, it transmits on thewatering hole assignment until directed by the OOB link 162 to stoptransmission or switch to a UE specific CF assignment. Thus, atconfiguration 615, e.g., when powered on from a “Power off” state 610,each UE appliqué 110 is assigned a unique code identifying the CF, aswell as CFs for valid eNodeB appliqué 120 watering hole spreadingcode/frequency combinations (the WHCFs 128). If no per-eNodeB appliquéCF has been assigned, the UE appliqué uses the WHCF 128 to transmit allPRACH bursts. Upon receipt of a PRACH burst at the eNodeB appliqué 120,the eNodeB appliqué 120 sends an OOB assignment to the UE to use one ofCFs reserved for that eNodeB appliqué 120 and the UE appliqué 110 entersa “Per-eNodeB appliqué CF Assigned” 620 state. In this states, the UEappliqué 110 continues to transmit using the designated CF 625, until aRACH is detected at the UE appliqué 110, from the UE 105, on a differentLTE physical center frequency 635. At that point, the UE 105 re-entersthe “No Per-eNodeB appliqué CF Assigned State” 630 and uses the WHCF forall transmissions.

FIG. 7 is a workflow 700 depicting aspects of some embodiments of thepresent invention. In some embodiments of the present invention, programcode executing at the first appliqué spreads an uplink signal of a userfrom an UE of a mobile computing device (710). The program codefrequency shifts (and/or optionally frequency hops), so that the spreadsignal from the UE maintains orthogonality over-the-air (720). Programcode executing at the second appliqué obtains the spread signal from theUE and processes the spread signal using an embedded training sequencesto equalize and de-spread each symbol, and re-combines the resultingde-spread and frequency-shifted signal using an aggregator (730). Theprogram code of the second appliqué provides the recombined signal to aneNodeB (740). In some embodiments of the present invention, the programcode executing at the first appliqué spreads the uplink signal utilizinga spreading code assigned by the program code utilizing an OOB controlchannel. In some embodiments of the present invention, the program codeat the first appliqué access an OOB control channel to providefine-grain close-loop spreading code offset adjustments. In someembodiments of the present invention, the spreading code applied isspecific to the user. In some embodiments of the present invention, thespreading codes are arbitrary. In some embodiments of the presentinvention, the spreading codes are obtained from a centralizedrepository on a shared computing systems, including but not limited to acloud computing system.

FIGS. 8-9 expand on aspects of this workflow 700, individually in the UEApplique (e.g., FIG. 1, 110) and the eNodeB Applique (e.g., FIG. 1,120), in various embodiments of the present invention.

FIG. 8 is a workflow 800 that further illustrates certain aspects ofsome embodiments of the present invention with a focus on aspectsperformed in the UE Applique 110 and/or by various programs thatinteract with the UE Applique 110. For illustrative purposes only,references are made to elements of the FIG. 1. This workflow 800 can beunderstood by referencing aspects of FIG. 1. In some embodiments of thepresent invention a LTE UE 110 is a COTS (Commercial Off-The-Shelf) UE,which is shown in FIG. 1 with separate transmit 154 and receive 153antenna ports. In an embodiment of the present invention a Time-Syncblock 137 determines the beginning of each LTE UL waveform subframe andsymbol period (810). The UE SPIRAL appliqué 110 utilizes the beginningof each LTE UL waveform subframe and symbol period to align a spreadingcode with the transmitted waveform from the LTE UE (820). This can beaccomplished, for example, by determining the time offset of theDe-Modulation Reference Symbols (DMRSs) using a cross-correlationbetween signal from the LTE UE Tx port (the LTE UL waveform) and theexpected DMRS waveform. In some embodiments of the present invention, aSpreading Wfm/LO block (Spreading Waveform/Local Oscillator) 126generates a spreading waveform (for direct-sequence spreading) and alocal oscillator (either at a pre-determined fixed frequency or afrequency that changes at pre-determined times, in the case of frequencyhopping) (830). The program code applies the output of this block to thewaveform available at the output of the Training Sequence Insertionblock 124, by performing a functional equivalent of complex basebandmodulation 148 (the operation can be applied at baseband, IF, or RF)(840). The Training Sequence Insertion block 124 creates a trainingsequence, which is orthogonal or approximately orthogonal to the LTE ULTx waveform such that the training sequences do not interfere withreception of the LTE UL Tx waveform (850). The program code adds thetraining sequence to the LTE UL Tx waveform to create the output of theTraining Sequence Insertion block (860). Based on the output of theTraining Sequence Insertion block 124, the MAED block at the ESAreceiver 159 performs per-symbol-period channel equalization/trackingand de-spreading with low latency (870). The OOB Rx (Out Of BandReceiver) 162 receives control information from the OOB Tx 173 (Out OfBand Transmitter) at the eNodeB SPIRAL Applique (ESA) 120 (880). TheUESA Controller 129 processes information from the OOB Rx 162, such ascode/frequency (CF) assignments and training sequences assignments,which controls the Training Sequence Insertion 124 and Spreading Wfm/LO126 blocks (890).

FIG. 9 is a workflow 900 that further illustrates certain aspects ofsome embodiments of the present invention with a focus on aspectsperformed in the eNodeB Applique and/or by various programs thatinteract with the eNodeB Applique. This workflow 900 can also beunderstood by referencing aspects of FIG. 1. In an embodiments of thepresent invention, and RF to BB 199 converter converts RF signals todigital baseband representations for each of the Receive Antennas (ESARx 1, . . . , ESA Rx N_(r)) (910). The multi-channel data from the RF toBB block 199 is processed by (1) the Watering Hole Code/Frequency MAED(WHCF MAED) receive processor 128, (2) K instantiations of theuser-specific MAED processors (User n MAED) 134, and (3) theinterference estimator (INT Est) 198 (920). Each of the Multi-ApertureEqualization/De-spreading (MAED) blocks perform multi-apertureSpace-Time Adaptive Processing (STAP) (including interference mitigationusing input from the INT Est block) to equalize the signal received fromeach UESA, as well as de-spreading for the designed Code/Frequency (CF),providing N_(a) outputs (930). Each MAED uses the training sequencesinserted at the UESA 110 by the Training Sequence Insertion block 124 toestimate the channel, enabling low latency STAP processing (940). A WHCFMAED 128 performs the MAED function for uplink signals assigned to theWHCF code/frequency channel, while the per-user MAED blocks (User n MAED134) perform this function for user-specific CF spreading waveformsassigned to each UESA 110 (950). An INT Est (Interference Estimation)block 198 estimates the frequency-dependent spatial signature ofinterfering signals which can be used in the MAED STAP function tomitigate heterogeneous interference (e.g., jamming) (960). An Aggregator137 assembles the outputs from the MAED processors and combines themwith appropriate time alignment for subsequent processing, afterconversion from baseband to RF using the BB To RF converter 161, by theeNodeB (970).

Embodiments of the present invention include a computer systemcomprising: a first appliqué comprising at least one processor, coupledto user equipment connected to a mobile network; the user equipmentconfigured to communicate with Evolved Node B hardware over the mobilenetwork; a second appliqué comprising at least one processor, coupled tothe Evolved Node B hardware, configured to receive communications fromthe user equipment and to process and transmit the communications to theEvolved Node B hardware; and the Evolved Node B hardware, where thefirst appliqué spreads an uplink signal of a user from the userequipment and frequency shifts the uplink signal, so that the spreaduplink signal maintains orthogonality over the mobile network, and wherethe second appliqué obtains the spread uplink signal from the userequipment and processes the spread uplink, the processing by the secondappliqué comprising: utilizing embedded training sequences to equalizeand de-spread each symbol of the spread uplink signal to generate ade-spread and frequency-shifted signal; re-combining the de-spread andfrequency-shifted signal using an aggregator to generate a recombinedsignal; and providing the recombined signal to the Evolved Node Bhardware. The user equipment in some embodiment is user equipment of along-term evolution system. The Evolved Node B hardware, in someexamples, comprises a base transceiver station. In some embodiments, theuser equipment comprises a mobile handset.

In some embodiments of the present invention, the first appliqué spreadsan uplink signal utilizing a spreading code unique to the user. Thespreading code can be provided to the user equipment by the secondappliqué, and the spreading code can be provided to the first appliquéby the user equipment.

In some embodiments of the present invention, the first appliqué spreadsthe uplink signal of the user from the user equipment by performingactivities comprising: determining a beginning of each uplink (UL)waveform subframe and symbol period in the uplink signal, where theuplink signal comprises a waveform; utilizing the beginning of each ULwaveform subframe and symbol period to align a spreading code with thewaveform; generating, from the uplink signal, a spreading waveform and alocal oscillator at a given frequency; embedding the training sequencesin the waveform; and applying the spreading waveform and the localoscillator at the given frequency to the waveform with the trainingsequence to generate the spread uplink signal. In some embodiments ofthe present invention, the applying comprises performing a complexbaseband modulation. In some embodiments of the present invention, thetraining sequences added to the waveform are orthogonal or approximatelyorthogonal to the waveform. In some embodiments, the given frequency isselected from the group consisting of: a fixed frequency and a dynamicfrequency, where the dynamic frequency changes at pre-determined times.

Embodiments of the present invention include a computer-implementedmethod, the method comprising: spreading, by one or more processors of afirst appliqué, an uplink signal of a user from long-term evolutionsystem user equipment, where the first appliqué is coupled to thelong-term evolution system user equipment, and where the long-termevolution system user equipment is connected to a mobile network; andfrequency shifting, by the one or more processors of the first appliqué,the spread uplink signal to maintain orthogonality over the mobilenetwork.

The method can further comprise: obtaining, by one or more processors ofa second appliqué, over the mobile network, the spread uplink signal,where the second appliqué is coupled to Evolved Node B hardware, andwhere the Evolved Node B hardware is configured to receivecommunications from the long-term evolution system user equipment; andprocessing, by the one or more processors of the second appliqué, thespread uplink signal, where the processing comprises: utilizing embeddedtraining sequences to equalize and de-spread each symbol of the spreaduplink signal to generate a de-spread and frequency-shifted signal; andre-combining the de-spread and frequency-shifted signal using anaggregator to generate a recombined signal; and providing, by the one ormore processors of the second appliqué, the recombined signal to theEvolved Node B hardware.

In some embodiments of the present invention, the method furthercomprises obtaining, by the one or more processors of a first appliqué,from the long-term evolution system user equipment, a spreading code,where the spreading comprises utilizing the spreading code. Thespreading code can be unique to the user. The method can also includeassigning, by the one or more processors of a second appliqué, to thelong-term evolution system user equipment, the spreading code. Theassigning can include: accessing, by the one or more processors of asecond appliqué, an out-of-band channel; and utilizing, by the one ormore processors of a second appliqué, the out-of-band channel to assignthe spreading code. The spreading can further include: determining, bythe one or more processors of the first appliqué, a beginning of eachuplink (UL) waveform subframe and symbol period in the uplink signal,where the uplink signal comprises a waveform; utilizing, by the one ormore processors of the first appliqué, the beginning of each UL waveformsubframe and symbol period to align a spreading code with the waveform;generating, by the one or more processors of the first appliqué, fromthe uplink signal, a spreading waveform and a local oscillator at agiven frequency; embedding, by the one or more processors of the firstappliqué, the training sequences in the waveform; and applying, by theone or more processors, the spreading waveform and the local oscillatorat the given frequency to the waveform with the training sequence togenerate the spread uplink signal. In some embodiments of the presentinvention, the training sequence added to the waveform is orthogonal orapproximately orthogonal to the waveform. In some embodiments of thepresent invention, the given frequency is selected from the groupconsisting of: a fixed frequency and a dynamic frequency, where thedynamic frequency changes at pre-determined times.

Embodiments of the present invention include a computer-implementedmethod that comprises: obtaining, by one or more processors of a secondappliqué, over the mobile network, a spread uplink signal, where anuplink signal spread to generate the spread uplink signal originatedfrom long-term evolution system user equipment, where the secondappliqué is coupled to Evolved Node B hardware, and where the EvolvedNode B hardware is configured to receive communications from thelong-term evolution system user equipment; and processing, by the one ormore processors of the second appliqué, the spread uplink signal, wherethe processing comprises: utilizing embedded training sequences toequalize and de-spread each symbol of the spread uplink signal togenerate a de-spread and frequency-shifted signal; and re-combining thede-spread and frequency-shifted signal using an aggregator to generate arecombined signal; and providing, by the one or more processors of thesecond appliqué, the recombined signal to the Evolved Node B hardware.

FIG. 10 illustrates a block diagram of a resource 400 in computersystem, such as, which is part of the technical architecture of certainembodiments of the technique. Returning to FIG. 10, the resource 400 mayinclude a circuitry 502 that may in certain embodiments include amicroprocessor 504. The computer system 400 may also include a memory506 (e.g., a volatile memory device), and storage 508. The storage 508may include a non-volatile memory device (e.g., EEPROM, ROM, PROM, RAM,DRAM, SRAM, flash, firmware, programmable logic, etc.), magnetic diskdrive, optical disk drive, tape drive, etc. The storage 508 may comprisean internal storage device, an attached storage device and/or a networkaccessible storage device. The system 400 may include a program logic510 including code 512 that may be loaded into the memory 506 andexecuted by the microprocessor 504 or circuitry 502.

In certain embodiments, the program logic 510 including code 512 may bestored in the storage 508, or memory 506. In certain other embodiments,the program logic 510 may be implemented in the circuitry 502.Therefore, while FIG. 10 shows the program logic 510 separately from theother elements, the program logic 510 may be implemented in the memory506 and/or the circuitry 502. The program logic 510 may include theprogram code discussed in this disclosure that facilitates thereconfiguration of elements of various computer networks, includingthose in various figures.

Using the processing resources of a resource 400 to execute software,computer-readable code or instructions, does not limit where this codecan be stored. Referring to FIG. 11, in one example, a computer programproduct 500 includes, for instance, one or more non-transitory computerreadable storage media 602 to store computer readable program code meansor logic 604 thereon to provide and facilitate one or more aspects ofthe technique.

As will be appreciated by one skilled in the art, aspects of thetechnique may be embodied as a system, method or computer programproduct. Accordingly, aspects of the technique may take the form of anentirely hardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system”. Furthermore,aspects of the technique may take the form of a computer program productembodied in one or more computer readable medium(s) having computerreadable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readable signalmedium may include a propagated data signal with computer readableprogram code embodied therein, for example, in baseband or as part of acarrier wave. Such a propagated signal may take any of a variety offorms, including, but not limited to, electro-magnetic, optical or anysuitable combination thereof. A computer readable signal medium may beany computer readable medium that is not a computer readable storagemedium and that can communicate, propagate, or transport a program foruse by or in connection with an instruction execution system, apparatusor device.

A computer readable storage medium may be, for example, but not limitedto, an electronic, magnetic, optical, electromagnetic, infrared orsemiconductor system, apparatus, or device, or any suitable combinationof the foregoing. More specific examples (a non-exhaustive list) of thecomputer readable storage medium include the following: an electricalconnection having one or more wires, a portable computer diskette, ahard disk, a random access memory (RAM), a read-only memory (ROM), anerasable programmable read-only memory (EPROM or Flash memory), anoptical fiber, a portable compact disc read-only memory (CD-ROM), anoptical storage device, a magnetic storage device, or any suitablecombination of the foregoing. In the context of this document, acomputer readable storage medium may be any tangible medium that cancontain or store a program for use by or in connection with aninstruction execution system, apparatus, or device.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readable signalmedium may include a propagated data signal with computer readableprogram code embodied therein, for example, in baseband or as part of acarrier wave. Such a propagated signal may take any of a variety offorms, including, but not limited to, electro-magnetic, optical or anysuitable combination thereof. A computer readable signal medium may beany computer readable medium that is not a computer readable storagemedium and that can communicate, propagate, or transport a program foruse by or in connection with an instruction execution system, apparatusor device.

Program code embodied on a computer readable medium may be transmittedusing an appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thetechnique may be written in any combination of one or more programminglanguages, including an object oriented programming language, such asJava, Smalltalk, C++ or the like, and conventional proceduralprogramming languages, such as the “C” programming language, PHP, ASP,assembler or similar programming languages, as well as functionalprogramming languages and languages for technical computing (e.g.,Matlab). The program code may execute entirely on the user's computer,partly on the user's computer, as a stand-alone software package, partlyon the user's computer and partly on a remote computer or entirely onthe remote computer or server. In the latter scenario, the remotecomputer may be connected to the user's computer through any type ofnetwork, including a local area network (LAN) or a wide area network(WAN), or the connection may be made to an external computer (forexample, through the Internet using an Internet Service Provider).Futhermore, more than one computer can be used for implementing theprogram code, including, but not limited to, one or more resources in acloud computing environment.

Aspects of the technique are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions, also referred to as software and/orprogram code, may also be stored in a computer readable medium that candirect a computer, other programmable data processing apparatus, orother devices to function in a particular manner, such that theinstructions stored in the computer readable medium produce an articleof manufacture including instructions which implement the function/actspecified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowchart and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the technique. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

In addition to the above, one or more aspects of the technique may beprovided, offered, deployed, managed, serviced, etc. by a serviceprovider who offers management of customer environments. For instance,the service provider can create, maintain, support, etc. computer codeand/or a computer infrastructure that performs one or more aspects ofthe technique for one or more customers. In return, the service providermay receive payment from the customer under a subscription and/or feeagreement, as examples. Additionally or alternatively, the serviceprovider may receive payment from the sale of advertising content to oneor more third parties.

In one aspect of the technique, an application may be deployed forperforming one or more aspects of the technique. As one example, thedeploying of an application comprises providing computer infrastructureoperable to perform one or more aspects of the technique.

As a further aspect of the technique, a computing infrastructure may bedeployed comprising integrating computer readable code into a computingsystem, in which the code in combination with the computing system iscapable of performing one or more aspects of the technique.

As yet a further aspect of the technique, a process for integratingcomputing infrastructure comprising integrating computer readable codeinto a computer system may be provided. The computer system comprises acomputer readable medium, in which the computer medium comprises one ormore aspects of the technique. The code in combination with the computersystem is capable of performing one or more aspects of the technique.

Further, other types of computing environments can benefit from one ormore aspects of the technique. As an example, an environment may includean emulator (e.g., software or other emulation mechanisms), in which aparticular architecture (including, for instance, instruction execution,architected functions, such as address translation, and architectedregisters) or a subset thereof is emulated (e.g., on a native computersystem having a processor and memory). In such an environment, one ormore emulation functions of the emulator can implement one or moreaspects of the technique, even though a computer executing the emulatormay have a different architecture than the capabilities being emulated.As one example, in emulation mode, the specific instruction or operationbeing emulated is decoded, and an appropriate emulation function isbuilt to implement the individual instruction or operation.

In an emulation environment, a host computer includes, for instance, amemory to store instructions and data; an instruction fetch unit tofetch instructions from memory and to optionally, provide localbuffering for the fetched instruction; an instruction decode unit toreceive the fetched instructions and to determine the type ofinstructions that have been fetched; and an instruction execution unitto execute the instructions. Execution may include loading data into aregister from memory; storing data back to memory from a register; orperforming some type of arithmetic or logical operation, as determinedby the decode unit. In one example, each unit is implemented insoftware. For instance, the operations being performed by the units areimplemented as one or more subroutines within emulator software.

Further, a data processing system suitable for storing and/or executingprogram code is usable that includes at least one processor coupleddirectly or indirectly to memory elements through a system bus. Thememory elements include, for instance, local memory employed duringactual execution of the program code, bulk storage, and cache memorywhich provide temporary storage of at least some program code in orderto reduce the number of times code must be retrieved from bulk storageduring execution.

Input/Output or I/O devices (including, but not limited to, keyboards,displays, pointing devices, DASD, tape, CDs, DVDs, thumb drives andother memory media, etc.) can be coupled to the system either directlyor through intervening I/O controllers. Network adapters may also becoupled to the system to enable the data processing system to becomecoupled to other data processing systems or remote printers or storagedevices through intervening private or public networks. Modems, cablemodems, and Ethernet cards are just a few of the available types ofnetwork adapters.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising”, when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or steps plus function elements in the descriptions below, if any,are intended to include any structure, material, or act for performingthe function in combination with other elements as specifically noted.The description of the technique has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular uses contemplated.

The invention claimed is:
 1. A computer system comprising: a firstappliqué comprising at least one processor, coupled to user equipmentconnected to a mobile network; the user equipment configured tocommunicate with Evolved Node B hardware over the mobile network; asecond appliqué comprising at least one processor, coupled to theEvolved Node B hardware, configured to receive communications from theuser equipment and to process and transmit the communications to theEvolved Node B hardware; and the Evolved Node B hardware, wherein thefirst appliqué spreads an uplink signal of a user from the userequipment and frequency shifts the uplink signal, so that the spreaduplink signal maintains orthogonality over the mobile network, andwherein the second appliqué obtains the spread uplink signal from theuser equipment and processes the spread uplink, the processing by thesecond appliqué comprising: utilizing embedded training sequences toequalize and de-spread each symbol of the spread uplink signal togenerate a de-spread and frequency-shifted signal; re-combining thede-spread and frequency-shifted signal using an aggregator to generate arecombined signal; and providing the recombined signal to the EvolvedNode B hardware.
 2. The system of claim 1, wherein the user equipment isuser equipment of a long-term evolution system.
 3. The system of claim1, wherein the Evolved Node B hardware comprises a base transceiverstation.
 4. The system of claim 1, wherein the user equipment comprisesa mobile handset.
 5. The system of claim 1, wherein the first appliquéspreads the uplink signal utilizing a spreading code unique to the user.6. The system of claim 5, wherein the spreading code is provided to theuser equipment by the second appliqué, and wherein the spreading code isprovided to the first appliqué by the user equipment.
 7. The system ofclaim 1, wherein the first appliqué spreads the uplink signal of theuser from the user equipment by performing activities comprising:determining a beginning of each uplink (UL) waveform subframe and symbolperiod in the uplink signal, wherein the uplink signal comprises awaveform; utilizing the beginning of each UL waveform subframe andsymbol period to align a spreading code with the waveform; generating,from the uplink signal, a spreading waveform and a local oscillator at agiven frequency; embedding the training sequences in the waveform; andapplying the spreading waveform and the local oscillator at the givenfrequency to the waveform with the training sequences to generate thespread uplink signal.
 8. The system of claim 7, wherein the applyingcomprises performing a complex baseband modulation.
 9. The system ofclaim 7, wherein the training sequences added to the waveform areorthogonal or approximately orthogonal to the waveform.
 10. The systemof claim 7, wherein the given frequency is selected from the groupconsisting of: a fixed frequency and a dynamic frequency, wherein thedynamic frequency changes at pre-determined times.
 11. Acomputer-implemented method comprising: assigning, by the one or moreprocessors of a second appliqué, to long-term evolution system userequipment, a spreading code; obtaining, by the one or more processors ofa first appliqué, from the long-term evolution system user equipment,the spreading code; spreading, by one or more processors of a firstappliqué, utilizing the spreading code, an uplink signal of a user fromthe long-term evolution system user equipment, wherein the firstappliqué is coupled to the long-term evolution system user equipment,and wherein the long-term evolution system user equipment is connectedto a mobile network; and frequency shifting, by the one or moreprocessors of the first appliqué, the spread uplink signal to maintainorthogonality over the mobile network.
 12. The computer-implemented ofclaim 11, further comprising: obtaining, by one or more processors of asecond appliqué, over the mobile network, the spread uplink signal,wherein the second appliqué is coupled to Evolved Node B hardware, andwherein the Evolved Node B hardware is configured to receivecommunications from the long-term evolution system user equipment; andprocessing, by the one or more processors of the second appliqué, thespread uplink signal, wherein the processing comprises: utilizingembedded training sequences to equalize and de-spread each symbol of thespread uplink signal to generate a de-spread and frequency-shiftedsignal; and re-combining the de-spread and frequency-shifted signalusing an aggregator to generate a recombined signal; and providing, bythe one or more processors of the second appliqué, the recombined signalto the Evolved Node B hardware.
 13. The computer-implemented method ofclaim 11, wherein the spreading code is unique to the user.
 14. Thecomputer-implemented method of claim 11, wherein the assigning furthercomprises: accessing, by the one or more processors of a secondappliqué, an out-of-band channel; and utilizing, by the one or moreprocessors of a second appliqué, the out-of-band channel to assign thespreading code.
 15. The computer-implemented method of claim 11, whereinthe spreading further comprises: determining, by the one or moreprocessors of the first appliqué, a beginning of each uplink (UL)waveform subframe and symbol period in the uplink signal, wherein theuplink signal comprises a waveform; utilizing, by the one or moreprocessors of the first appliqué, the beginning of each UL waveformsubframe and symbol period to align the spreading code with thewaveform; generating, by the one or more processors of the firstappliqué, from the uplink signal, a spreading waveform and a localoscillator at a given frequency; embedding, by the one or moreprocessors of the first appliqué, the training sequences in thewaveform; and applying, by the one or more processors, the spreadingwaveform and the local oscillator at the given frequency to the waveformwith the training sequences to generate the spread uplink signal. 16.The computer-implemented method of claim 15, wherein the trainingsequences added to the waveform are orthogonal or approximatelyorthogonal to the waveform.
 17. The computer-implemented method of claim11, wherein the given frequency is selected from the group consistingof: a fixed frequency and a dynamic frequency, wherein the dynamicfrequency changes at pre-determined times.
 18. A computer-implementedmethod comprising: obtaining, by one or more processors of a secondappliqué, over a mobile network, a spread uplink signal, wherein anuplink signal spread to generate the spread uplink signal originatedfrom long-term evolution system user equipment, wherein the secondappliqué is coupled to Evolved Node B hardware, and wherein the EvolvedNode B hardware is configured to receive communications from thelong-term evolution system user equipment; and processing, by the one ormore processors of the second appliqué, the spread uplink signal,wherein the processing comprises: utilizing embedded training sequencesto equalize and de-spread each symbol of the spread uplink signal togenerate a de-spread and frequency-shifted signal; and re-combining thede-spread and frequency-shifted signal using an aggregator to generate arecombined signal; and providing, by the one or more processors of thesecond appliqué, the recombined signal to the Evolved Node B hardware.